The Bubble V2 Carb Cap by White Rhino is new and improved. The bottom of the carb cap has a small directional airhole which can be adjusted while taking a hit to effectively vaporize concentrates.
When using a carb cap, airflow within the banger is improved. Different types of carb cap designs promote different kinds of airflow. This airflow maintains lower temps within the banger and allows more concentrate to be pulled.